Question

Identify the mystery number.

My Tens place has a digit that is less than 8 but more than 5. If you add my two digits together, you get 10. What number am I?

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

Say: Let’s find out what the mystery number is.

Steps:
$\bullet$ My Tens place has a digit that is less than 8 but more than 5.
$\bullet$ So, the digit in the Tens place of the mystery number has to be 6 or 7.
$\bullet$ Also, when both the digits of the mystery number are added, we get a total of 10.
$\bullet$ When 6 and 4 are added we get 10, and when 7 and 3 are added we get 10. These are the only possible solutions.
$\bullet$ The abacus given in Option C has 7 beads over “T” representing 7 Tens and 3 beads over “O” representing 3 Ones.
$\bullet$ 7 Tens and 3 Ones = 73.
$\bullet$ So, the mystery number is 73.
$\bullet$Hence, Option C is correct.